Electric wrenches are tools powered by power supplies or batteries and used for tightening bolts. The electric wrenches mainly include impact wrenches, shear wrenches, constant torque wrenches, torque angle wrenches, angle wrenches, hydraulic wrenches, torque wrenches, rechargeable electric wrenches and the like. The electric wrenches have the characteristics of convenient operation and time and labor conservation. As they are mainly used for mounting high-strength bolts of steel structures in the steel structure installation industry, high demands are proposed on the torque of the wrenches.
In the prior art, the work of an electric wrench generally involves a motor connected with a power supply and a transmission mechanism driven by the motor. Energy is transferred to a whip block by the transmission mechanism, and the work task is accomplished by means of striking a working head by the whip block.
However, the impact mechanism of such structure is provided with only one whip block which, when working, causes quite a few separations in the housing. As such, the output efficiency is reduced and the toque is low. In addition, in order to achieve periodic striking, an eccentric wheel or an asymmetric structure are usually adopted as the structure of the whip block, so dynamic balance of the whip block during the operation cannot be ensured.